<!--
     Any copyright is dedicated to the Public Domain.
     http://creativecommons.org/publicdomain/zero/1.0/
-->
<html>
<style>
.a {
  background-color: rgb(0,255,0);
}
#b {
  width: 200px;
  height: 210px;
}
.c {
  width: 100px;
  height: 100px;
  mix-blend-mode: difference;
}
#d {
  z-index: 1;
  position: absolute;
  top:80px;
}
</style>
<div id="b" class="a">
  <div id="d">.
    <div class="a c"></div>
  </div>
</div>
</html>
